AUSTIN, TX — 1:53 p.m. Central Time: Facebook PR director Brandee Barker gave me this exclusive scoop: CEO Mark Zuckerberg, who's due to take the stage for his SXSW Interactive keynote in minutes, is not wearing his famous Adidas flip-flops.

In other news, Julia Allison just chewed me out and then gave me a granola bar. Daft Punk is playing on the sound system.

2:07 p.m.: Zuckerberg says now that Facebook's available in Spanish, people are using Colombia to organize resistance against guerrilla armies. Wait — does that mean it's actually a tool of oppression?

2:08 p.m.: Facebook is about communicating "efficiently," Zuckerberg keeps saying. Efficient? Does he even use Facebook?

2:09 p.m.: Lacy asks Zuckerberg about terrorism. "Facebook has a relatively large population in London," says Zuckerberg. "Terrorism comes ... from a lack of empathy and understanding. People are growing up, they're relatively poor, they spend a lot of time studying with their imam. At the same time, they'll go out with their friends and drink on Friday nights and try to meet girls. Then they take pictures of themselves with their religious leaders holding guns. There are people who are at a point in their lives, a crossroads, deciding whether they're going to pursue terrorism. And people have told me that Facebook has helped them maintain connections with friends in Europe, in America, and maintain that empathy."

In other news, Zuckerberg's shoe:

2:13 p.m.: Lacy recounts the first time she interviewed Zuckerberg. "He's wearing a white T-shirt, and he was so nervous, he was sweating through his shirt," says Lacy. "The first time I inteerviewed Mark, I kept asking broader and broader questions, trying to get him to talk. Finally he said, 'I don't know how to answer that question. It's too broad.' I said, 'Mark, I'm trying to get you to say more than two words.' Mark said, 'That's really hard.' I said, 'Three words.'"

Right after Lacy's tale, Mark said, "What was the question?"

2:16 p.m.: I think Zuckerberg is talking about how antipoverty activists used Facebook to organize protests at a senator's church, home, and office.

Beacon isn't even a part of our ad team. It's part of our platform team. We think these large social networking sites are going from large monolithic sites like facebook.com ... to social services. A lot of them aren't even things we're building. Some of them are going to be inside facebook.com. An increasing amount of that is going to be outside facebook.com. What we were trying to do with Beacon was taking the first step with letting people take actions on other parts of the Web and feed back into what their friends are doing. It also ties into the ad system, because it can be an endorsement — someone you care about is doing something, that's much more effective.

2:29 p.m.: Lacy makes the apt point — argued earlier in Valleywag — that complaints about News Feed were much larger than Beacon protests, but suggests the larger concern about both features is privacy. Zuckerberg points out that people are much more likely to put their cell phone on Facebook because they're allowed to control which people see it.

2:32 p.m.: Why do I feel a strong urge to take a nap whenever Zuckerberg talks about "platforms" and "ecosystems"? I think he's saying he's trying to reduce application spam with algorithms. Because that worked so well with email, right?

2:34 p.m.: Lacy asks about rumors in the Financial Times that Facebook is talking to the record labels about building an iTunes killer. "What's up with that?" "I don't know," says Zuckerberg, deadpan. He then concedes that Facebook is talking to several companies, but there's "nothing to announce."

2:36 p.m.: "So you're Forbes's youngest billionaire," says Lacy. "We're just not focused on that," says Zuckerberg. Can't he just play a recording of the soundbite? That seems easier. The $15 billion valuation, he says, came about because the company wanted to raise the most money with the least dilution. "High expectations are tough," he concedes. "Having such a focus on money in the business can be tough for us, because it can self-select for people who are interested in that. We don't want people to join the company because they're going to make money very quickly."

2:39 p.m.: Ah, the IPO question. "It's not that we're opposed to going public," says Zuckerberg. "[The $15 billion valuation] throws down the gauntlet" to potential acquirers, observes Lacy. "For certain companies, that's the goal, to go public" or get sold, says Zuckerberg. "Yahoo offered us a billion dollars a few years back. The primary analysis that we were doing wasn't, 'Are we worth $1 billion?' We said, we have a chance to build a platform that fundamentally changes how people connect or communicate. How many times in your life do you have that chance? So we decided to go for it."

2:43 p.m.: "Did you get rid of some people who wanted to [sell to Yahoo]?" asks Lacy. "We made some management changes," says Zuckerberg. Is that a reference to recently departed COO Owen Van Natta? Or former CFO Mike Sheridan, who was replaced by Gideon Yu?

2:45 p.m.: "Let's talk about Sheryl [Sandberg]," says Lacy. "She's been called the token grownup." "We just passed this mark where we have 500 employees," says Zuckerberg. "That's crazy. I feel really lucky to have her."

2:46 p.m.: "How do you think she's going to negotiate that male-dominated environment?" asks Lacy. "She has a great track record of doing that. I don't think that will be an issue," says Zuckerberg. I note that Zuckerberg didn't dispute Lacy's observation.

2:48 p.m.: "Is it hard from you to step back from product management? Because you'd really be working on the product, right?" asks Lacy. (Zuckerberg recently tapped longtime Facebook executive Matt Cohler to run product management.) "CEO is more of a full-time job than I'd admitted," says Zuckerberg. "The CEO sets the tone for the organization. Being CEO is a good way to make sure the company focuses on that — that people keep their eyes on what's important."

2:52 p.m.: "You're a computer guy and you write longhand on paper," observes Lacy, who reveals that Zuckerberg takes notes in bound books. "Fantastic question," quips Zuckerberg, which provokes howls of laughter from the audience. Zuckerberg then takes away Lacy's glass of water, just to be safe.

2:57 p.m.: Audience questions. First one up is your typical privacy-and-sharing paranoiac. "I think the reason we don't have a lot of that stuff yet is that we haven't come up with both controls and good default settings so people don't have to do a lot of work," says Zuckerberg. "Facebook is still relatively constrained as a company. Things take time. We've realized that it's an issue."

3:00 p.m.: "Other than really rough interviews, what are the toughest obstacles Facebook faces?" asks a wiseacre. "Is he making fun of me or of you?" Zuckerberg asks Lacy.

3:02 p.m.: "Do you think Google's pissed that you have so much data trapped on Facebook?" asks an audience member. "They don't get pissed," says Zuckerberg. "They're nice guys." Then he gives some incredibly boring answer about "semi-private" and "semi-public" information. Five-word version: Good luck with that, Google.